Power augers are made by many companies and come in many sizes usually 8 inch diameter is common. All the augers that I have seen use the same principal with the whole blade rotating the same way, cutting the hole with one pair of blades. Most augers are designed with a centrifugal clutch with a small gear mounted to the centre of the output side. This turns a bigger gear giving a fairly high gear reduction. This bigger gear is attached to the auger shaft.